At 206.1 persons per sq. km., Burundi has the second-largest population density in Sub-Saharan Africa. Most people live on farms near areas of fertile volcanic soil. The population is made up of three major ethnic groups--Hutu, Tutsi, and Twa. Kirundi is the most widely spoken language, French and Kiswahili also are widely spoken. Intermarriage takes place frequently between the Hutus and Tutsis. The terms "pastoralist" and "agriculturist," often used as ethnic designations for Tutsi and Hutu, respectively, are only occupational titles which vary among individuals and groups. Although Hutus encompass the majority of the population, historically Tutsis have been politically and economically dominant.